Conventional apparatus for producing sand molds for foundry purposes have a composite mold unit comprising a frame, molding box and pattern device. The molding unit is filled with molding material from a filling unit and is then moved beneath a compression unit. The compression unit and molding unit tightly contact one another such that the molding material in the molding unit can be subsequently compacted. When the molding material is introduced into the molding unit in conventional apparatus, it often exceeds the top edge of its frame requiring the molding material to be flattened in preparation for the compacting process. When the molding material is flattened or leveled, some of the molding material will unavoidably fall upon the top edge of the molding frame providing its sealing surface. However, the sealing surface must be adequately prepared or cleaned to permit the molding unit to be sealed to the compression unit. The preparation of the sealing surface is usually accomplished by brushing or blowing the molding material off the sealing surface.
Within the overall operation of compacting systems, the required cleaning process requires a relatively long time. Thus, the conventional cleaning process disadvantageously affects the predetermined cycle duration for the molding material compacting system.